In a free standing space dividing wall panel system of the type employed in the modern open office plan, desks and/or work surfaces of various types are still an essential element. In some systems, conventional free standing desks or work surface tables are employed which are not interconnected with the wall panel system. However, in many such systems the desks or work surfaces are mounted directly to the wall panel and are supported solely by the wall panel system. Several different mechanisms are utilized to mount the desk or work surface to the wall panel including L-shaped cantilever members and stretcher rails. A stretcher rail is a rail like member that is mounted flush against the panel and serves to support the edge of the desk or work surface which is against the wall panel. Since most wall panel systems include wall panels of a number of different lengths in order to provide for flexibility of office design, it is necessary to manufacture stretcher rails in as many different sizes as there are wall panel lengths in the system. Having to manufacture and inventory a number of different sized stretcher rails can involve substantial expense and a system which would allow stretcher rails to accommodate more than a single size panel would constitute a meaningful improvement in manufacturing and storage costs.